Clamp for cutting machines



May 8, 1934- R. F. HYMAN 1,957,711

CLAMP FOR CUTTING MACHINES Filed July 6, 1932 Patented May 8, 1934 UniresAres rArNr eprice l2 Claims.

This invention relates to new and useful attachments for paper cuttingmachines and particularly to paper cutting machines of the guillotinetype.

The principal object of the invention is to provide a device for use inconjunction with inachines of the above character which will effectivelyclamp a stackof sheets of paper in the machine and prevent slipping ortwisting of the respective sheets during the cutting operation.

Another object of the invention is to provide a device of the presentcharacter which effectively clamps and locks the stack of sheets ofpaper in a rm grip in the machine during the entire cutting operation.

Another object of the invention is to provide a device as describedwherein the paper is clamped and locked in position automatically whenthe paper is placed in the machine, and is automatically unclamped whenthe paper is removed after being cut.

A more specific object of the invention is to provide a novel clampingdevice as set forth which may be attached to the customary back gage ofacutting machine and when once in position is automatic in operation andrelieves theoperator of the machine from attending or operating theclamp.

Other objects and .details of construction of the invention are set`forth hereinafter and shown inthe accompanying drawing,.in which:

Figure l is a fragmentary View in section of a cutting machine showingthe device constituting the present invention associated therewith;

Fig. 2 is a view inplan of the device;

Fig. 3 is a view in side elevation of the device disclosed in Fig. 2having a portion of the back gage cut away to show the mounting of theclamping device.

Fig. 4 is a view similar to Fig. 3 showing the device in lockedpositionto firmly clampthe stack of paper in the machine; and

Fig. 5 is a view in perspective of portions of the clamping device whichare available to alter the size-thereof for various sizes of stacks ofsheets to be cut.

Heretoforain paper cutting machines ofthe present character,considerable difficulty has been present in a tendency for therespective sheets of a stackto twist a small degree with respect to eachothercausing the uneven cutting thereof. ,Certain clamping devices havebeen devised and adapted to travel with the cuttingknifeand clampthepaper with increasing force asthe cutter descendsthroughthe stack.

These clamps have been only partially successful since the stackedsheets were not clamped on the machine table immediately upon theplacing of the paper in the machine.

By the present invention a clamping device is provided for lockingstacked sheets of paper in a cutting machine immediately the .stack isplaced in the machine in position for cutting'. The paper is firmlylocked in position and will so remain until such time as the paper isremoved therefroin. The clamp is automatic in operation, requires noattention when once set, and clamps the stacked paper irrespective andindependently of the operation of the cutter and other movements of themachine.

Referring now more particularly to the drawing, the invention is shownin conjunction with a paper cutting machine comprising side framemembers 1 separated by channel or other niembers 2 and having thecustomary table 3 on which the stacked sheets of paper A rest. A backgage 4 -is adjustably mounted on the rear portion of the table 3 and isprovided with a plurality of forwardly extending parallel spaced fins orflanges 5 against the forwardends 5a of which the stacked sheets of.paper A abut. The customary knife stock 6 carryingra knife blade 7moves vertically between guide niem bers 8 and 9 respectively.

The novel clamping device forming the subject of the present inventioncomprises a bracket consisting of sides 1G and 11 respectively which arespaced with respect to each other by an end piece 12 residingintermediate said side members and adjacent the rear thereof. Thebracket is arranged to be positioned inthe space intermediate theparallel flanges 5 of the back gage 4, as shown in Figs. 3 and 4 of thedrawing and it should be noted that the width of the bracket justdescribed, may be substantially equal to the width of the spaceintermediate the flanges 5 so that the bracket will ll the space and bemore firmly supported by the back gage, the said bracket-being rmlysecured inthe space intermediate the flanges 5-by any means and such abolt 14.

it should be further noted that the forward ends 13 of the sides i0 and1l of the bracket, residein a planesubstantially flush with the forwardend. surface 5a of the flanges -5 sothat the operation of the clampingdevice will not be interferred with.

An arm 15 is pivotally mounted as at 16, 1ntermediate the sides 10.and11 of thefbracket and it should be noted that the pivot point 16 icothereof is offset forwardly from the Vertical center line of the saidarm 15 and is so positioned with respect to the sides of the bracketthat the forward end face 15a thereof is substantially flush with theforward end faces 13 of the sides of the bracket and the forward endfaces a of the flanges 5 when in the position to clamp a stack ofsheets.

The arm 15 pivots about the point 16 against the action of a spring 17,one end of which is connected to a pin 18 residing in the recess 19formed in the rear end face of said arm, the other end of the saidspring being adjustably connected to the member 12 by means of a screw20 which cooperates with a threaded element 21 threaded into the rearend of the spring. The arrangement just described permits the tension ofthe spring to be adjusted so that suihcient force may be exerted on thepivotal arm to maintain said arm in its normal position. Grooves 22 and23 are formed adjacent the extremity of the forwardly projecting portion13b of the arm 13 in such a manner as to provide a substantiallyvertical runner' 24 arranged to reside in a slot 25 in the clamp member26.

The vertical position of the member 26 with respect to the projection13b of the arm may be predeterminedly fixed by suitable adjusting meanssuch as a wing nut 27 and bolt 28 which extends through the slot in theclamp piece 26.

An extension 29 is provided and is arranged for positioning intermediatethe lower extremity of the member 26 and a contact piece 30 so that theclamp may be readily adjusted for effective use with stacks cf sheets ofvarious heights. The lower end of the member 26 is provided with aninwardly extending bore 31 arranged to receive a projection 32 on theextension 29 and retained therein by a lock bolt 32. The upper surfaceof the contact piece is provided with a similar projection 32a arrangedfor insertion in the inwardly extending bore 3l in the clamp piece 26 ora similar bore 33 in the lower extremity of the extension 29 as may bedesired, depending upon the height of the stack of sheets to be cut.

The normal position of the clamp, when there is no stack of material inposition for the cutting operation, is disclosed in Fig. 3 of thedrawing, the said clamp being normally maintained in that position, bythe action of the spring 17 described above.

When a stack of sheets of material is to be cut, the back gage 4 isadjusted upon the table 3 in order that the sheets cut by the knife '9will be of the desired predetermined dimension when one side of thestack of sheets is in abutting relation with the ends 5a of the parallelspaced flanges 5 of the said gage 4. When a stack of sheets A abuts theends of said flanges 5 in the manner set forth, that part of the arm 15normally projecting outwardly beyond the end faces 5a of the flangesbelow the pivot point 16, is moved inwardly intermediate the sides 10and 11 of the bracket and the forward end face 13a of the arm l5 assumesa position ush with the ends of the bracket and the flanges 5a causingthe contact piece 30 to correspondingly pivot and engage the' top sheetof the stack A with suflicient pressure to rmly maintain the sheets inproper relation during the cutting operation.

It should be noted particularly that the longitudinal axis of the runneror guide 24 is disposed at an angle obliquely with respect to thevertical center-line of the arm 15 and positions the clamp elementsimilarly at an angle with respect to said arm.

As shown in Fig. 4, when the member 30 contacts with the uppermost sheetof paper, the clamp extends inwardly from its upper end at an angleoblique to the now true vertical centerline of the arm 15. Thisarrangement of the clamp effectively locks the stacked sheets A firmlyin position for the cutting operation and prevents the relative twistingof the several sheets with respect to each other during the verticaldownward passage of the knife blade '7. The sheets will be firmly heldby the clamp in the manner set forth irrespective of any other operationof the machine until the stack of cut sheets is moved away from theIianges 5, to permit the spring 17 to pivot the arm 15 about the point16 and releasing the member 30 from Contact with the sheets.

While I have set forth the embodiment of my invention for the purpose ofdescription, it will be apparent that certain modifications in thedetailed construction thereof and certain changes in form necessarilyincident to its application to cutting machines of various forms, may beincorporated within the scope of the appended claims.

What is claimed is:

l. In a cutting machine having a bed for supporting material to be cut,a back gage, and means pivotally mounted with respect to said gage forautomatically clamping and locking said material rmly on the bed whenthe material abuts the gage in position for cutting, said meansautomatically releasing the material immediately said material isremoved from contact with said gage.

2. In a cutting machine having a bed for supporting material to be cut,a back gage, means pivotally mounted with respect to said gage forclamping the material rmly on the bed as long as the material abuts theback gage, and means operable to release the clamp and free the materialimmediately said material is removed from contact with the back gage.

3. A clamping device comprising a bracket, an arm pivotally mounted withrespect to said bracket, the pivot point for said arm being offsetforwardly of the longitudinal center line of said arm and suitablypositioned so that, when the arm is in a vertical position, the frontend face thereof will be flush with the front end face of the bracket, acontact arm carried by said pivot arm and disposed at an angle obliqueto the longitudinal center line of the latter, and means connectedintermediate the pivot arm and the bracket tending to pivot the formerand raise the contact arm.

4. A clamping device comprising a bracket, an

arm pivotally mounted with respect to said bracket, the pivot point forsaid arm being offset forwardly of the longitudinal center line of saidarm and suitably positioned so that, when the arm is in a verticalposition, the front end face thereof will be flush with the front endface of the bracket, an adjustable contact arm carried by said pivot armand disposed at an angle oblique to the longitudinal center line of thelatter, and a spring connected intermediate the pivot arm and thebracket tending to pivot the former and raise the contact arm.

5. A cutting machine having a bed for supporting material to be cut, acutting knife movable vertically with respect to the table, a back gageadjustably mounted on the bed, said back gage having forwardly extendingspaced parallel anges thereon, means for clamping the material to thebed mounted in the space intermediate said flanges, said meanscomprising a bracket, the outer end faces of which are ilush with theend faces of the flanges, an arm pivotally mounted in said bracket, thepivot point thereof being offset forwardly of the longitudinal centerline of the arm and positioned in the bracket so that when said arm issubstantially vertical the front end face is ush with the ends of thebracket and the flanges of the gage, a contact arm adjustably mounted onthe pivot arm and disposed at an angle oblique with respect to thevertical center line of said pivot arm, and a spring connectedintermediate the pivot arm and the bracket acting to pivot the arm in aclockwise direction and maintain the contact arm out of engagement withthe material toy be cut when said material does not abut the end facesof the bracket and flanges.

6. A cutting machine having a bed for supporting material to be out, acutting knife movable vertically with respect to the table, a back gageadjustably mounted on the bed, said back gage having forwardly extendingspaced parallel flanges thereon, means mounted in the space intermediatesaid anges for securing the material to the bed, said means comprising abracket, an arm pivotally mounted in said bracket, the pivot pointthereof being offset forwardly of the longitudinal center line of thearm, and a contact arm adjustably mounted on the ivot arm and disposedat an angle oblique with respect to the vertical center line of saidpivot arm.

7. A cutting machine having a bed for supporting material to be cut, acutting knife movable vertically with respect to the table, a back gageadjustably mounted on the bed, said back gage having forwardly extendingspaced parallel flanges thereon, means mounted in the space intermediatesaid anges for clamping the material to the bed, said means comprising abracket, an arm pivotally mounted in said bracket, the pivot pointthereof being oifset forwardly of the longitudinal center line of thearm, a contact arm adjustably mounted on the pivot arm and disposed atan angle oblique with respect to the vertical center line of said pivotarm, and a spring connected intermediate the pivot arm and the bracketacting to pivot the arm and move the Contact arm out of engagement withthe material when removed from contact against the back gage.

8. A cutting machine having a bed for supporting material to be cut, aback gage mounted thereon, means mounted in the back gage for clampingthe material to the bed, said means comprising a bracket, an armpivotally mounted in said bracket, the pivot point thereof being Offsetforwardly of the longitudinal center line of the arm and positioned inthe bracket so that when said arm is substantially vertical the frontend face is flush with the ends of the bracket and the gage, a contactarm adjustably mounted on the pivot arm and disposed at an angle obliquewith respect to the vertical center line of said pivot arm, and a springconnected intermediate the pivot arm and the bracket acting to pivot thearm in a clockwise direction and maintain the contact arm out ofengagement with the material when removed from contact against the backgage.

9. A cutting machine having a bed for supporting material to be cut, agage mounted thereon, means mounted on said gage for clamping thematerial to the bed, said means comprising a bracket, an arm pvotallymounted in said bracket, a contact arm adjustably mounted on the pivotarm and disposed at an angle oblique with respect to the verticalcenter-line of said pivot arm, and means connected between the pvot armand the bracket, tending to pivot said arm and maintain the same out ofengagement with the material when the latter is removed from contactagainst the gage.

l0. A cutting machine having a bed for supporting material to be cut, aback gage adjustably mounted on the bed, said back gage having forwardlyextending spaced parallel anges thereon, means mounted in the spaceintermediate said flanges for clamping the material to the bed, saidmeans comprising a bracket, an arm pivotally mounted in said bracket, acontact arm adjustably mounted on the pivot arm, and a spring connectedintermediate the pivot arm and the bracket acting to pivot the arm andmove the contact arm out of engagement with the material when removedfrom contact against the back gage.

1l. in a machine for cutting through stacks of sheets of paper, meansassociated with said machine 'and operable independently thereof toautomatically engage said stack when the latter is in cutting positionand prevent relative movement of said sheets with respect to oneanother, said means also being automatically operative to release saidstack when the latter is removed from cutting position.

12. In a machine for cutting through stacks of sheets of paper, thecombination with a gauge, of means operatively associated therewith toautomatically engage said stack when abutting said gauge and preventrelative movement of said sheets with respect to one another, said meansalso being automatically operative to release said stack when the latteris removed from contact with said gauge.

ROBERT F. HEYMAN.

